When building, despite the help that is already in there (observation tower, pressing Ctrl) I frequently find myself in a position (literally) that makes aligning a building difficult. This is a problem in particular when trying to align something on two axis. It is usually straightforward to do this for one of the two axis but often when I left click to place the building I find I slightly misplaced it. Unfortunately this only becomes apparent upon closer (literally) inspection.
I therefore suggest adding a shortcut to temporarily untie the positioning of the preview from the point the camera is looking at. This would allow to walk around the preview and confirm its proper placement from all angles.